As to increasing the drag by 2%, can you check that as my instinct would say .002 as that is a huge increase in drag
cD_shrouds = diameter_shrouds * length_shrouds * 2 * cd / area_sail, with cd of tubes, ropes etc. of about 1.
Going from 3mm to 5mm of 2 * 6m shrouds for a boat with 14m² sail area creats a delta drag of 0.0017. If the total drag of your boat is around 0.1, than you have an estimated drag increment of 1.7% = 2%.
Cheers,
Klaus
